The present disclosure relates to toners and processes useful in providing toners suitable for electrophotographic apparatuses, including apparatuses such as digital, image-on-image, and similar apparatuses. In particular, the disclosure relates to toner additives, namely, a fluorinated surfactant to improve toner charging. The term “fluorinated surfactant” and “fluorosurfactant” will be used interchangeably. The incorporation of such additives into toners, in particular, emulsion aggregation (EA) toners, have provided improved charging without any significant adverse impact on the other properties of the toner.
In embodiments, the surfactant is incorporated into the latex at the emulsion polymerization stage of the EA process. By doing so, the surfactant is better distributed and retained in the toner core. The surfactant boosts charging, which improves the overall parent charge, charge maintenance and blocking performance of the toner. In addition, the low foaming surfactant reduces the coarse generation in the downstream processing, such as toner making and washing; thus improving the overall yield.
Numerous processes are within the purview of those skilled in the art for the preparation of toners. Emulsion aggregation is one such method. These toners are within the purview of those skilled in the art and toners may be formed by aggregating a colorant with a latex polymer formed by emulsion polymerization. For example, U.S. Pat. No. 5,853,943, the disclosure of which is hereby incorporated by reference in its entirety, is directed to a semi-continuous emulsion polymerization process for preparing a latex by first forming a seed polymer. Other examples of emulsion/aggregation/coalescing processes for the preparation of toners are illustrated in U.S. Pat. Nos. 5,403,693, 5,418,108, 5,364,729, and 5,346,797, the disclosures of each of which are hereby incorporated by reference in their entirety. Other processes are disclosed in U.S. Pat. Nos. 5,527,658, 5,585,215, 5,650,255, 5,650,256 and 5,501,935, the disclosures of each of which are hereby incorporated by reference in their entirety.
In general, toners comprise at least a binder resin, a colorant and one or more additives, including external surface additives. Any resin binder suitable for use in toner preparation may be employed without limitation. The properties of a toner are influenced by the materials and amounts of the materials of the toner.
Electrophotography, which is a method for visualizing image information by forming an electrostatic latent image, is currently employed in various fields. The term “electrostatographic” is generally used interchangeably with the term “electrophotographic.” In general, electrophotography comprises the formation of an electrostatic latent image on a photoreceptor, followed by development of the image with a developer containing a toner, and subsequent transfer of the image onto a transfer material such as paper or a sheet, and fixing the image on the transfer material by utilizing heat, a solvent, pressure and/or the like to obtain a permanent image.
As with all toner designs there is a constant need for new methods or chemicals that can improve the overall toner charging performance.